During the last decades, use of portland limestone cement has shown a rapid increase, especially due to its lower environmental impact during the production phase in comparison with portland cement. However, these environmental advantages should be correlated to the long-term performance of concrete structures. The knowledge of the long-term properties, and particularly the durability performance of reinforced concrete structures, is essential to assess the actual environmental impact of the replacement of portland cement with ground limestone. Several studies were carried out since the late 1970s on the properties of limestone portland concrete. Some authors claim that limestone participates to the reactions of cement hydration, whilst, for others, limestone does not have any hydraulic property and behaves as an inert material. As far as compressive strength is concerned, several authors assert that compressive strength is relatively unaffected by limestone replacement up to 15% with respect to the total mass of binder, whilst when the percentage of limestone increases, the strength is reduced compared to portland, which indicates that limestone behaves as an inert addition. According to some authors an increase of early-age strength occurs with limestone additions (5-20%) due to the improvement in particle packing, increase of cement hydration rate, early production of calcium carbo-alluminate and the formation of nucleation sites of calcium hydroxide crystals. As far as the durability behaviour of portland limestone cement is concerned, there is still disagreement and the contribution of limestone to the resistance to chloride and carbonation penetration is controversial. In this paper the effect of the percentage of replacement of portland cement clinker with ground limestone, water/binder ratio and cement content on compressive strength, electrical resistivity and resistance to carbonation and chloride penetration of concrete was evaluated. Results showed that the replacement of portland clinker with 15% of limestone led to a reduction in 28-day mechanical strength and 28-day electrical resistivity and to an increase of the accelerated carbonation coefficient and the rapid chloride migration diffusion coefficient. These variations were further enlarged with the replacement of 30% of limestone. Concretes with equal compressive strength experienced the same resistance to carbonation independently from the amount of clinker replaced with limestone, indicating that, provided the compressive strength requirement is guaranteed, also the resistance to carbonation penetration is achieved. Conversely, concretes with equal compressive strength experienced a lower resistance to chloride penetration.